Preparation of reactor effluent for recovery of acetylene and the like therefrom



July 12, 1960 R. c. scoFlELD Y PREPARATION oF 2 Sheets-Sheet l Filed May 19, 1958 njl. 0

July 12, 1960 R. c. scoFlELD 2,945,075

PREPARATION OF REACTOREFFLUENT FOR RECOVERY OF ACETYLENE AND THE LIKE THEREFROM 2 Sheets-Sheet Filed May 19, 1958 N @Pi INVENTOR RC. SCOFIELD BY Ms@ ATTORNEYS MONEIU ZOmm U INN mm2; ruzmzox Verational costs.

,StateSPatent PREPARATION 0F REACTOR EFFLUENT FOR RE- COVERY 0F ACETYLENE AND THE LIKE THEREFROM lRaymond C. Scoeld, Bartlesville, Okla., assignor to Phillips Petroleum Company, a corporation of Delaware y Filed May 19, 1958, Ser. N0. 736,282

Y 1'6 Claims. (Cl. 26o-#679) l a i This 4invention relates to the manufacture of acetylene, lparticularly quenching, scrubbing, and cooling hot reacetylene has resulted in considerable effort directed to- 'ward its production by high temperature cracking of low molecular weight, normally gaseous hydrocarbons, such as methane, ethane, propane, butane, natural gas, and the like, in a thermal cracking furnace. `Normally, the hot furnace or reactor eluent gases, containing acetylene uand other low molecular weight cracked gases, are subjected to quenching' and scrubbing operations to cool the gases, and remove undesirable components such as tars, aromatics, carbon black and condensible vapors. FollowingV the quenching antd scrubbingoperations, the cracked gases are then compressed, dried, and the acetylene and other valuable cracked products are recovered and purified.

Many of the quenching operations heretofore proposed, patented, or used in commercial operations require a great deal of expensive heat exchange and cooling surface, which surface is often subjected to fog-laden vapors and tar-bearing liquid streams with the result that polymeric `materials and other undesirable contaminants often tend to. deposit on this surface in such a manner as to reduce the eiciency thereof. Other quench systems require l deionized or condensate makeup water, and in many cases require reprocessing of the quench media to remove contaminants, thereby increasingthe installation and op- In still other quenching systems the cooled and quenched cracked gases contain prohibitive amounts 'of undesirable cracked petroluem products, such as. tars, etc., as a result of the ineflicient scrubbing operation.

' Accordingly, an object of this invention is to overcome the aformentioned problems by the. provision of an improved method and apparatus for preparing low molecular weight cracked gases for recovery and purification of valuable cracked products therefrom, such asv acetylene. Another object is, to provide an improved method. andapparatus for quenching, scrubbing, and cooling hot acetylene-containing effluent gasesobtained from4 a thermal cracking furnace. Av further object is. to provide an improved method and apparatus for quenching effluent gases from4 a thermal crackingl furnace or the like, which method and apparatus are characterized by an ecient and `economicalheat exchange. operation, minimum polymer formation and deposition, on. the. inner walls of processing equipment,` and other advantages. Further objectsand advantages of this invention will becomeapparent to those 2,945,075 Patented July l2, i960 skilled in the art from the following discussion, appended claims and drawing in which:

Figures 1 and 2 are diagrammatic ow sheets illustrating various embodiments of this invention.

Referring now to the drawing, in which like parts have been designated with like reference numerals, and initially to Figure l, a thermal cracking furnance or reactor generallyl designated 10 is shown. Reactor l0 is preferably a tangential burner-reactor such as that disclosed and claimed in U.S. Patent 2,750,434, issued June l2, 1956, to Joseph C. Krejci. As disclosed in U.S. Patent 2,750,434, the tangential burner-reactor, or furnace system, contains two cylindrical sections, one of which may be termed a precombustion section, and the other, a reaction section. These two sections are adjacent each other and coaxial, and are preferably disposed horizontally. The combustion section is positioned upstream from the reaction section and ordinarily has a shorter length and a larger diameter as compared to the adjacent disposed reaction section. In Figure l, a combustible fuel mixture, such as a mixture of natural gas and oxygen, is passed via line 11 into the precombustion chamber of said reactor ltl in a direction tangential to its inner side Wall, while at the same time hydrocarbon reactant is axially introduced via line 12 into theV combustion section ofthe furnace, alone or withaddition'al oxygen or air supplied via line i3. The tangentially `introduced fuel is burned, upon or prior to entrance, into the combustion chamber, and the resulting total hot product of burning, i.`e., combustion gases, comes into contactrand in direct heat exchange relation with the axially introduced hydrocarbon charge;V The tangentiallyY added mixture is injected into the Vcombustion chamber of the furnace at a sulciently high velocity to cause combustion gases formed therein to flow spirally inward, and subsequently helically downstream'through the reaction section. Combustion gases thus formed, together withaxially introduced hydrocarbon reactant is passed into the reaction section in an initial state of annular separation. The helically moving combustion gases form a gas blanket adjacent the reactor wall, and in this manner, direct contact of the hydrocarbon reactant with the reaction chamber walls is substantially prevented, and carbon deposition is greatly reduced.

The hydrocarbon reactant or charge can be one of various hydrocarbon cracking stocks, such as methane, ethane, propane, butane, natural gas, and light vaporizable, low molecular weight hydrocarbons. In some cases, it may be desirable to axially introduce the hydrocarbon charge along with steam. The specific reaction temperature used will depend upon the product desired and the hydrocarbon reactant employed` Generally, the reaction temperature employed for the predominant production of olens will be in the range between. about 13'00 and 1900 F., and the temperature range for the production of acetylene will be from about 1900 to 5500"` F. Within these temperature ranges carbon deposit is greatly minimized or `entirelyeliminated and light oleninc hydrocarbons, particularlyl ethylene and propylene, and acetylene are produced and. recovered in high yield, together with aromatic hydrocarbons, higher molecular weight olens and acetylenes, valuable parafhns, and the like, as by-products. The cracking reaction is also accompanied by the formation of tars and other undesirable components and it is some extent lowers the temperature of the eliluent. The reactor effluent and water vapor are then conducted from the furnace via a reactor effluent line 16, the latter preferably being a rather long pipe so that the eiuent is in indirect heat exchange with the atmosphere to elect further cooling of the reactor effluent. y

The reactor eluent, having a temperature between about 470 and 800 F., is passed via pipe 16 to a vertically vdisposed two-stage quench and scrubbing tower generally designated 17, and introduced in the bottom section thereof. Quench tower 17 is divided into a lower quench section 18 and an upper quench section 19 by an intermediate liquid take-off tray 21, such as a doughnut tray. The lower and upper quench sections 18, 19 are provided with vapor-liquid contacting means generally designated 22, which may be baffles, bubble cap trays, Schneible trays, or the like. The reactor etiluent gases plied with cooling water via line 43, which is returned via line 44.

The condensate accumulating on the take-olf tray 37 is withdrawn via line 46 and pumped to a suitable heat exchanger 47 where the water -is further cooled, and subsequently passed to a refrigerant exchanger 48 where vit is further cooled, `the resultant oooledwater then being returned via line 27 to the spray means 26 in the upper end of the quench tower 17 The quench water in line 27 can be supplemented-when desired by the addition of make-up water supplied via line 49, and a small amount Aof water containing dissolved solids discarded Via lline 50.

Y Alternatively, the condensate on tray 37 can be pumped flow upwardly in the lower quench section 18 in countercurrent relation to quench oil, such as mineral seal oil, sprayed by means 23 in the upper end thereof, the quench oil, having a temperature between about 130 and 190 P., being supplied to the quench tower via line 24. The direct contact of the reactor eiuent with the quench oil results in some further cooling of the reactor effluent, eg., to a temperature between about 150 and 205 F., and results in scrubbing the eEluent to effect the removal of tars and aromatic components therefrom. The partially cooled reactor efliuent gases then flow upwardly through the upper quench section 19 in countercurrent vrelation with quench Water that issprayed by means 26 in the upper end thereof, the quench water,` having a temperature between about 85 to 105 F., being supplied to the tower via line 27. Upon direct contact'of the refV actor effluent gases with the quench water, additional cooling is effected and condensable vapors removed from said 'eflluent The major portion of the liquid condensate accumulated on tray 21,'having a temperature between about 150 and 195 KF., is removed from the upper quench section 19 by means of condensate withdrawal line 28. The spent oil quench media, having a temperature between about 305 and 390 F. and containing absorbed tars and aromatics, is withdrawn from the lower end of the lower quench section 18 by means of withdrawal line 29. The quenched and scrubbed reactor euent gases, having a temperature between about 95 and 165 F., are removed from the upper end of quench tower 17 via conduit 31 and are then subsequently compressed and further cooled and passed to recovery and purication equipment, such as that disclosed and claimed in U.S. Patent 2,814,359, issued November 26, 1957, to R. A. Koble.

The quench media in Withdrawal lines 28, 29 is then conveyed to a vacuum flash tower generally designated 32 via line 33. Flash tower 32 is preferably intermedilately divided into a lower section 34 and upper section 36 by means of a liquid take-olf tray 37, such as a doughnut tray. The flash tower 32 is maintained under a sub-atmospheric pressure or vacuum by suitable means. For example, the upper end of the flash tower 32Vcommunicates with a line 38 so as to permit the withdrawal of overhead, which `line is connected to a suitable steam jet ejector generally designated 39, theoverhead being thus conveyed via line 41 to the upper section 19 of quench tower 17. The quench media from quench tower 17 is cooled by passing it via line 33 into the lower ash tower section 34 with the result that a minor portion of the quench water is immediately flashed, the major portion of quench water and the oil settling in the tower bottom. The water vapor from the ilashed quench media passes upwardly into the upper flash section 36 and the major portion thereof is cooled and condensed upon contact with the cooled condenser surfaces of a condenser vgenerally designated 42 which is disposed within the upper flash tower section 36, said condenser being supv'upper quench section 19 of the two-stage quench tower y17. Water evaporated in ash tower 64 isV preferably Areplaced, by fresh treated cooling tower `make-up water back to the reactor 10 via lines 53, 14 to initially quench the reactor effluent.

The flash tower bottoms, generally comprising five times as much water as oil by weight, and having a temperature between about 137 to 146 F., are removed from the lower end of flash tower 32. via withdrawal line -5-1 and pumped to a suitable liquid separation zone gen-v ysettling tank 52 and cooled by an indirect heat exchanger to 95 F.' and conveyed to the spraying means 26 in the Yupper portion of quenchtower 17 Tars and other contaminants can be'removed from settling tank 52 yia withdrawal line 54. f

Referring now to Figure 2, another embodiment of .this invention is shown which in some respects is similar to that shown in Figure l. In Figure-2 the water required for the initial quench of the reactor efliuent is supplied and pumped via line 61 from the liquid take-off tray 3-'7 of a primary vacuum flash towerV 62 which in some aspects is similar to vacuum ash tower l32 of Figure l.

The water from the settling tank 52 of Figure 2, at a temperature of about 141 F., is supplied and pumped via linek 63 to a secondaryflash tower generally designated 64 where it is further cooled by evaporation to about 95 F. This ash tower is in some respects similar to the primary flash tower 62 in that it is intermediately divided into a lower flash section 66 and upper flash section 67 by a liquid take-off tray 68. The secondary flash tower 64 is also maintained at sub-atmospheric pressure or vacuum by means similar to that utilized in maintaining the primary vacuum flash tower 62 under vacuum. However, the flash tower overhead from the secondary vacuum flash tower 64 is conveyed via lines V69 and 71 to the upper Ysection 36 of the primary vacuum ash tower 62. In addition, cooling water is supplied via line 72 to spray means 73 in the upper section 67 of the secondary ash tower 64 so as to condense the water vapor resulting from the flashing operation. The llash tower bottoms from the secondary flash tower 64 are withdrawn via line 74 and pumped viaf line .76 back to the sprayy 'means 26 in the supplied via line 149 in 10 percent Vexcess amount, which amount' oisetsthe water 'discarded via, line 50 to limit Vthe build-up of dissolved solids. The condensate accumulating in the. take-off tray 68 of the secondary vacuum flash tower 64 is withdrawnand pumped via Vline 77 to the condenser42 disposed within the upper ,section 36 of theprimary'vacuum'flash tower 62, cooling `water being returned from the condenser via line 78.

' The advantages obtained by the practice of this invenntion are manyfold. Particularly, itis to be noted that the very'hot elliuent gases issuing from the reactor exit are vinitially quenched withoil rather water. As a result,

the fbnlk of tats .and other undesirable components are removed yfrom the reactor effluent at a high temperature Jlevel by `4absorption in the quench oil. Were water to `be usedffor quenching these hot gases, the `water would be immediately flashed, vgenerating large quantities of fst'eam whichwould tend-to carry overhead prohibitive amountsvot Stars and other contaminants, necessitating a large investment .in heat exchange .surface and further `operations to remove vthese contaminants from the eluent stream. Moreover, such an initial water quench would rely on mechanical contact and `condensation to effect `removal fof contaminants, whereas the initial oil quench -relies on `absorption of these contaminants by the oil. The feiective removal of tars, etc., by 'the practice of this invention, which utilizes to advantage a closed quench isystem, permits drying `and acetylene absorption to be carried out without a prior deoiling step and, in turn,

-allows heavy actylenes to be removed from the relatively Ismall acetylene product stream, rather than from the total cracked stream.

The water `quench media is cooled by the practice of -this invention by Autilizing its latent heat of vaporization :under vsub-atmospheric pressure. Further, heat 'exchange Asurface is not exposed to fog-laden vapors or tar-bearing liquid streams. Y

The operation ofthe above-described equipment ac- 'cordingto ,thepractice of this invention will now be Edescribed, and it Vshould be realized that certain apparatus,

`'suchwas valves, ow controllers, ratio flow controllers, Y

.meters, pressure indicating and recording equipment, tem- ;perature indicating and recording equipment, and the dike, aref-provided at .proper process poln'ts for maintaining proper control -of the processes of this invention, such f equipment, their installation and use: being well underfs'tood' byrthose skilled in theprocessing art. f

Referring agalnto Figure i1, 9,267 mols/s.d. of hydrocarbon charge-.stock prepared by preheating a mixture vofr5,'948 mols/sd. of a butane feed, `containing a small amount of butylenes and other unsaturates, is thermally *crackedewithin reactor .10 at a reaction temperature of about 2500" F. The reactor products, are initially quenched by spraying 41,800 mols/sd. of water within Ythe'downstream end of reactor 10, the'temperature of the lreactoreluent being lowered to about 1200 F. The refsultant effluent-steam mixture is then conducted from rei `actor 10 via line .16, the latter being preferably in heat exchange relationwith the atmosphere so as to eiect cooling of the rgases -to a temperature of about 600 F.,

fiat afrate of about 131,780 mols/s.d., of which 52,672

mols/sd. is Water. Quench oil, such as mineral seal-oil, -having a temperature-ofabout 141 F., is sprayed into *the upper end of the lower quench section 18 at a rate of about 22,936l rno'ls/sd. The rpsulting quenching and vscrubbing ofjthe gases results in the removal of Va large proportion of tars, heavy olenic hydrocarbon, aromatics -'andother contaminants which are absorbed in the quench oil, thus resulting in cooling these gases to a temperature `of about f176 F; The reactor efuent gases then iow upwardly through the upper quench section 19 in countercurrent relation with quench water sprayed into the upper end thereof, this quench water having a temperature of about 95 F. and sprayed at arate of about 72090 :hols/sd.` As 'a result of this directv contact, re-

Jsidual amounts of tars and other contaminants are removed from f'th'e gases, the resulting quenched, scrubbed,

fcooled 'gases being lremoved as overhead Vfrom the rich tower,17gat1'a1temperature of about 100 F. f The l' overhead `gaseous product, amounting to l84,363 'mols/s.d., visfthen directed tothe I'recoveryfand purification train, the

gg -p duct having the {following composition: 4

Mols/sd. CQ@y y3,6540 C02' 4,500

Mols/sd. CH, `4,410 C2H2 5,950 C2H4 1,659 'C3H4 119 "C4H2 200 gilHt 10(5) 1 Water 5,250

Liquid condensate is withdrawn from take-off tray 21 vi-a line 28 -at a temperature of about 160 F. and at a rate of about 837,603 mols/s.d., of which 131 mols/s.'d.' is oil, the remainder Water. The spent oil quench media, Acontaining the absorbed contaminants, is withdrawn from the lower portion of tower 17 via line 29 at a tempera- ,ture of about 350 F. and at a rate of 22,8001mo1s/s.d. 'The combined streams of liquid condensate and` spent 'quench oil is conveyed via line 33 to the flash tower 32, the latter having a pressure of about 155 mm. Hg, wherein the 'quench media is immediately flashed. Flash tower 32 is maintained under a vacuum by passing overhead amounting to 6 mols/s.d. via line 38 to steam fjet ejector 39, the latter being supplied with 34 pounds per hour steam, the resultant overhead-steam mixture being passed via line 41 to the upper portion of the quench tower 517. In the upper portion 36 of the dash tower 32, flash vapors are condensed on condenser surfaces of condenser 42, the latter being supplied with cooling water at a temperature of about F., this condenser having about 8,500 ft?. The ash tower bottoms are removed fromrlthe lower end ofthe dash tower 17 via line 51, ata rate of 795,667

mols/s.d., and pumped to settling tank 52, the Vtemper'ature of the latter being about 141 F. The water is withdrawn from settling tank S2 and pumped via line A`14 to the downstream end of reactor 10 at a temperature of about '141 F. and at a rate of about 41,800vmols/s.d. Alternatively, the condensate accumulated on tray 37 caribe withdrawnfrom the Hash tower 32 and pumped back to the'reractor 10 to initially quench the etluent gases. The condensate accumulated on tray 37 can also be withdrawn via lines 46, 27 to the upper end of the quench tower -17. Alternatively, water can be Withdrawn from settling tank S2 and passed to a suitable heat exchanger to eiect cooling to 95 F. and then sprayed in the upper end of quench tower 17. l

The quench oil employed in the practice of this invention is substantially any heavy oil, paral'nic or aromatic, which will llow and can be sprayed at the lowest temperatures involved. Gils which are preferably employed include benzene, toluene, anthracene, predominantly -aromatic kerosenes having, for example, a boiling point in the range of 200 F, to 500" F., and predominantly aromatic gas oil, such as a gas oil having a boiling range of 400 'F. to 700 F. A preferred oil is a heavy yaromatic oil which is produced in the cracking operation and permitted to accumulate in the process. A suitable oil which can be used for quenching according to this invention has the following specification:

Specic gravity at 60/ 60 F.=1.f0655 Kinematic viscosity at F.=14.38 centistokes Kinematic viscosity at 210 F.=2.86 centistokes Bureau of Mines Correlation Index=133 ASTM distillation, corrected to 760 mm. Hg.

Various modifications and alterations of this invention fbecome apparent to those skilled in the art without depart-ing from'the; scope and spirit of this invention, yand fit stobe understood that 'the latter'is 'not to `be limtedto y ammore .the foregoing discussion and accompanying drawing illus- 4trating vpreferred embodiments of this invention. -Iclaimz .Y v v v 1. Aprocess for quenching and scrubbing a high ternv-p'erature cracked gas containing acetylene recovered from the thermal conversion of hydrocarbons to produce acetylene-which Ycomprises passing said high temperar`ture cracked gas into the lower portion vof a two-stage `quenching zone; initially contacting said cracked Agas in the lower portion of said quenching zone with relatively Icooler quench oil in countercurrent llow; iinally contacting said cracked gas with quenchwater in the upper por- ,tion of said quenching zone in countercurrent flow; withdrawing the resulting quenched, relatively tar-free cracked gas containing acetylene as overhead from said upper portion of said quenching zone; withdrawing liquid condensate from said upper portion of said quenching zione; withdrawing spent oil from said lower portion of said 4quenching Zone; passing said liquid condensate and spent oil `tothe lower portion of a sub-atmospheric flashing lZone to effect evaporation of a minor portion of said liquid condensateand cause said spent oil and a major portion ,lof said liquid condensate to settle in thelower portion of said flashing zone; condensing the resulting water Ivapor in the upper portion of said llashing zone; withdrawing water and said settled spent oil from said lower lportion of said llashing zone and conveying the same to alliquidseparation zone; withdrawing oil from the Ylatter zone and passing the same to the upper end of said Alower portion of said quenching Zone for use as saidiquench oil; collecting liquid condensate accumulating in the lower end of said upper portion of said llashing zone; andwithdrawing said last-mentioned condensate from saidzflashing zone for use as quench media in the system.

2. In a process for manufacturing acetylene by the 'f nthermal conversion of a gaseous hydrocarbon in a ther- Wmal reactor, wherein a high temperature cracked gas 4comprisi-ng acetylene, olens, higher acetylenes and ole- -hns, aromatics, and tars, is initially quenched with water kintroduced inthe downstream end of said furnace, the Steps comprising passing said high temperature cracked `gas having a temperature in the range of 470 to 800 F. .into the lower portion of a two-stage quenching zone; f initially contacting said cracked gas in the lower portion of said quenching Zone with relatively cooler quench oil t .having a temperature in the range of 130 and 190 Vin countercurrent llow; linally contacting said cracked gasy with quench water having a temperature in therange of 85 to 105 F. in the upper portion of said quenching .zonein countercurrent iiow; withdrawing the resulting quenched, relatively tar-free cracked gas as overhead from said upper portion of said quenching zonegwithdrawing 'liquid condensate from said upper portion of said quench- Aing zone; withdrawing spent oil from said lower portion --of said quenching zone; passing said liquid condensate Y .and spent oil to the lower portion of a sub-atmospheric :flashing zone to elect evaporation of said liquid condensate and cause said spent oil to settle in the lower portion of said flashing Zone; condensing the resulting water vapor in the upper portion of said flashing Zone; withdrawing, said settled spent oil from said lower portion of said flashing zone and conveying the same to a liquid separation zone; withdrawing oil from the latter zone and pass- ',ing the same to the upper end of said lower portion of said quenching zone for use as said quench oil; collectingv Yliquidcondensate accumulating in the lower endof said lzupper portion of said flashing Zone; and passing `said acl-ic'umulated 'liquid condensateV backV to the system for use asquench media. v i" l lInria process'according torclairn'Z wherein said lastrnentionedliquid condensate is coolednand `returned to `said upper `portion Vof said quenchingl zone `for luse as said quench water, and wherein water is withdrawn trom ,said liquid separation zone and returned to said down-A stream end of said Yfurnace toinitially quenchsaid'reaclqr ellluent. v,

4. In a processi according to claim 2 wherein a major 'portion .of said, last-mentionedv accumulated liquid con- 5 .densateis cooled and returned to said upper portion of said quenching zone for use as said quenchwater, land a minor portion of said accumulated liquid condensate together with water withdrawn from said liquid separation Azone is returned to said downstream end of said furnace to initial-ly quench said reactor ellluent.

Y5. ln a processaccording to claim 2 wherein said lastmentioned accumulated liquid condensate `is returned to said downstream end of said reactor to initially quench said reactor eflluent; and wherein water is withdrawn 115 from said separation zone, cooled, and returned. to said upper portion of said quenching zone to serve as said quench water.

6. In a process for manufacturing acetylene by the thermal conversion of a gaseous hydrocarbonA in a thermal .20 reactor, wherein a high temperature cracked gas comprising acetylene, olens, 'higher acetylenes Yand oleiins, "aromatics, and tars, is initially. quenched with waterintroduced in the downstream end of 4said furnace, the steps comprising passing'said high temperatureV cracked gas having a temperature in the range of 470 to 800'F. into the lower portion' of ar two-,stage quenching zone; initially contacting said crackedigas in thelower portion -of said quenching zonefwith relatively cooler quench oil having a temperature inthe range of 130 and l90F. 'inV countercurrent liow; finallycontacting said cracked gas with quenchvwaterrhaving a temperature in the range of 85 to 105 F. in the-upper portion'of-*said quenching zone in countercurrent-llow; withdrawing-the resulting quenched, relatively'ltar-free cracked gas' aslloverhead from said upperV portion ofsaid quenchingzone; with- -drawing liquid condensate from said-upper portion of said quenching zone; withdrawing spent oil from said lower portion of said quenching-zone; passing said liquid condensate and spent oil to the lower portion lof a sub- 40 atmospheric flashing zone to` effect evaporation ofsaid liquid condensate and cause saidy spent oil 'toV settle in i the lower portion ofsaid flashing zone;'condensing the resulting water vapor 4in the'upper portion of said llashing lZone; withdrawing saidsettled spent oil from said g5-lower portion of said flashing-zone and conveying the same to a liquid separation zone; withdrawing oil from the latter zone and passing the same to the upper end of said lower portion of said quenching zone for use .as said quenchoil; collecting liquid condensate'accumulating 50.inthe lower end of said upper-portion of said flashing lone; withdrawing said condensate from said hashing zone and cooling the-same; passing theresulting cooled condensate back to said upper portion of said quenching vzione for use as said quench water; and withdrawing water from said liquid separation zone and returning the same to the downstream end of said reactor vso as to preliminarily quench said reactor efuent. 1.

7. In a process according to claim 6 wherein a portion of said condensate from said flashing tower is-also returned to said downstream endof said reactor.

8. In a'process for manufacturingvacetylene by the thermal conversion of a gaseous hydrocarbon in a thermal reactor, wherein a'high temperature cracked gas cornprising acetylene, olens,.higher acetylenes and olelins, aromatics,pand.tars, is initially quenched withwater introduced inthe downstream endof saidlfurnace, the steps YVcomprising passing-said highy temperature cracked 4gas ^hai/ins .a temperature in the range., 0f:y 4.70 t0V 80,071 1 into the lowergportionot av two-stage.- quenching z one;

0 initially.sgufactinggsaid Cracked gas in, the :19u/er. Pfrtivn ofV said quenching zone with lrelatively cooler quench oil havingfa temperature inthe rangeV of 130`and 190 F. 'Vincountercurrent ow; finally contacting said cracked gas with quench Iwater having a temperature in the range 751of to 105 F. inthe' upp'enportio-n'of said` quenching o'ne'in countercurrent How; withdrawing ,the resulting quenched, relatively tar-free cracked gas as overhead from',` said upper portion of said quenching zone; withdrawing liquid condensate from said upper portion of said( quenching zone; withdrawing spent oil from said lower portion of said quenching zone; passing said liquid condensate and spent oil to the lower portion of a subatmospheric flashing zone to ecct evaporation `of said liquid condensate and cause said spent oil -to settle in the lower portion of said hashing Zone; condensing the resulting water vapor in the upper portion of said tiashihgzone; withdrawing said settled spent oil from said lowerportion of saidilashing zone and conveying the same to a liquid separation zone; withdrawing oil from the `latter zone and passing the same to the upper end of saidV 'lower portion of said quenching zone for use as said quenchoil; collecting liquid condensate accumulating the lower end of said `upper portion of said flashing zon A;V withdrawing said condensate from said hashing vzone and passing the same back to the downstream endA ofsaid reactor so as toV preliminarily quench said reactor e'iilient; withdrawing water from said liquid separation z'on'e .and cooling the same; and. passing the resulting cooled water back to saidruppcr portion of said quenching zone for use as said quench'water.

9.v In a process for manufacturing acetylene by the v )thermal conversion or" a gaseous hydrocarbon in a thermal reactor, wherein a high temperature cracked gas comprising acetylene, oleiins, higher acetylenes and oleins, aromatics, and tars, is initially quenched with water introduced in the downstream end of said furnace, the steps fi-iiitially 'contacting said cracked gas in the lower portion o`f`said quenching zone with relatively cooler quench oil having a temperature in the range of 130 and 190 F.

comprising passing said high temperature cracked gas in'countercurrent flow; finally contacting said cracked l Y gas -with quench water having a temperature in the range of 85 to 105 F. in the upper portion of said quenching zone in countercurrent flow; withdrawing the resulting quenched, relatively tar-free cracked gas .as overhead fromrsaidmupper portion of said quenching zone; withdrawing, liquid condensate from said upper portion of said` quenching zone; withdrawing spent oil from said lower portion of said quenchingvzone; passing said liquid condensate and spentoil to theflower portion` of a subatmospheric hashing zone to relect evaporation of said liquid condensate and cause said` spent oil to settle in the lower portion of` said: flashingzone; condensing the resulting water Vapor in-the upper portion of: said flashinglzone; withdna'wir'ig said settled spent oil from said lower portion of said ilashing zone and conveying the same, to a liquid separation zone; withdrawing oil from the latter zone andpassingthe same to the upper end of Saidfflower portion of said quenching zone for use as 'said quench oil;rcollec`ting'liquid condensate accumulating in? theflower `end of said upper portion of said ashing zone; withdrawing said condensate fromY said flashing zone and passing the same back to the downstream end of lsaid 'reactor so as to preliminarily quench said reactor eluent; withdrawing water from said liquid separation zone and passing the same to the lower portion of a second similarV sub-atmospheric flashing zone, to efect r evaporation ofsaid4 water; passing relatively cooler water Ainto the upper'portion-'of' said second'- ilashing zone to efrect condensation of the resulting water vapor; collecting the resulting accumulated condensate in the upper portion of said second flashing zone; withdrawing said accumulated condensate and passing the same to said upper portion of said first iiashing zone; and withdrawing accumulated condensate in the lower portion of said second hashing zone and passing the same back to said upper portion of said quenching zone for use as said quench water,

' il) 10; Apparatus for quenchingnnd Vscrubbing a. gas fe'- covered from the thermal 'conversion of hydrocarbons from a thermal reactor,.which1comprises, incombinatoin; a two-stage gas-liquid contactI tower intermediately divided by liquid collecting means, having a gas passage therein, into lowerand upper4 quenching zones; gas-inlet means in. the lower part of said lowerv quenching zone; gasoutlet means in the upper part of said upper quenching zone; first liquid inlet means in the upper end ofsaid lower quenching zone; second liquid inlet means in the upper end of said'upper quenching zone; first liquid withdrawal outlet means inthe lower end of said lower quenching zone; second liquid 'withdrawal outlet means in thev lower end of said upper quenching zone and adapted to withdraw liquid from said liquid collecting means; first conduitm'eans operatively` connected to rst and second liquid withdrawal outlet means; a subatmospheri'c flash tower intermediately `divided by liquid collecting meansxinto and upper and lower zones; liquid inlet means in the lower part `of saidflower zone of said flash tower and operatively connected to said iirst conduit means; an'indirect heat exchanger disposed: in said upper zone of saidash tower; third liquid withdrawal'outlet means in theY lower end of said lower `zone of said ash tower; fourthA liquid withdrawal outlet means in the lower end of said` upper 'zone of said Hashv tower and operatively adapted to4v withdrawA liquid from said last-mentioned liquid collecting means; second conduit means operatively connected to said'third liquid withdrawal outlet means; arliquid settling tank operatively connectedto said last'- mentionedl conduitfmeans; third conduit means operatively connected to-said settling tank and said iirst liquid 'inlet means and adapted to supply the'same with quench media; and mea-nsV operatively connected to said vfourth liquid withdrawal outlet means andV adapted to return quench media therefrom to the system.V

il. Apparatus according to claim 10 wherein lsaid lastmentioned means comprises fourth conduit means operatively connected to said fourth liquid withdrawal outlet means andv indirect heat exchange vcooling means, and fifth conduitv means operatively connected to the latter and said second liquidI inlet means in the upper end of' said contact tower; and wherein said apparatus further comprisessixth conduit means operatively connected to 'adapted to supply the latter with said liquid condensate;

and' wherein said apparatus further comprises fifth conduitl means operatively connected to said settling tank and adapted to withdraw quench water from t-he latter and supply; the same to a direct heaty exchanger wherein said quench water is cooled; and sixth conduit means operativelyv connectedv to the latter heat exchanger and said second liquid inlet means in saidV upper end of said ContactV tower.

14: Apparat-us forquenching and scrubbing; a gas 4rectivered -from` the l'thermal conversion of hydrocarbons from a thermal reactor, which comprises, in combination; a two-stage gas-liquid contact tower intermediately divided by liquid collecting means, having a gas passage therein, into lower and upper quenching zones; gas-inlet means in the lower part of said lower quenching zone; gas-outlet means in the upper part of said upper quenching zone; rst liquid inlet means in the upper end of said lower quenching zone; second liquid inlet means in the upper end of said upper quenching zone; tirst liquid withdrawal outlet means in the lower end of said lower quenching zone; second liquid withdrawal outlet means in the lower end of said upper quenching zone and adapted vto withdraw liquid from said liquid collecting means; rst conduit means operatively connected to first and second l-iquid withdrawal outlet means; a sub-atmospheric flash tower intermediately divided by liquid collecting means into upper and lower zones; liquid inlet means in the lower part of said lower zone of said ash tower and operatively connected to said rst conduit means; an indirect heat exchanger disposed in said upper zone ofsaid ash tower; third liquid withdrawal outlet means inthe lower end of said lower zone of said flash tower; fourth liquid withdrawal outlet means in the lower end of said upper zone of'said ash tower and operatively adapted to withdraw liquid fromfsaid last-mentioned liquid collecting means; second .conduit means operatively connected tosaid third liquid withdrawal outlet means; a liquid settling .tank operatively connected to said last-mentioned conduit means; third conduit means operatively connected to Vsaid settling tankand said first Vliquid inlet means and adapted to supply the same with quench media; .fourth conduit means operatively connected to said fourth liquid withdrawal outlet means; indirect heat exchangecooling means operatively connected to said fourth conduit means; iifth conduit means operatively connected to said lastmentioned indirect heat exchange cooling means and operatively adapted to pass cooled liquid therefrom back to said second liquid inlet means inthe upper end of said contact tower;` and sixthconduit means operatively connected to said settlingtank and adapted to pass quench water therefrom to the 4downstream end of said reactor.

l5. Apparatus for quenching and scrubbing a gas re` covered from the thermal conversion of hydrocarbons from a thermal reactor, which comprises, in combination; a two-stage gas-liquid contact tower intermediately divided by liquid collecting means, having a gas passage therein, into lower andupper quenching'zones; gas-inlet means in the lower part of said lower quenching zone; gas-outlet means in the upper part of said upper quenching Zone; rst liquid inlet means in the upper end of said lower quenching zone; second' liquid inlet meansin the upper end of said yupper quenching Zone; `first liquid withdrawal outlet means in the lower end of said lower quenching zone; second liq- .uid withdrawal outlet means in the lower end of said upper quenching zonef and adapted to withdraw .liquid from said liquid collecting means; rst conduit means loperatively connected to iirst and second liquid withdrawal outlet means; a sub-atmospheric ash tower intermediately divided by liquid Ycollecting means into upper and lower zones; liquid inlet means in the lower part of .said lower zone of said fiash tower and operatively connected to said first conduit means; an indirect heat exchanger disposed in said upper zone of said ash tower; third liquid withdrawal outlet means in the lower end of said lower zone of said flash tower; fourth liquid withdrawal outlet means in the lower end of said upper zone of said ash tower and operatively adapted to withdraw liquid from said last-mentioned liquid collecting means; second conduit means operatively connected to said third liquid withdrawal outlet means; a liquid settling tank op` eratively connected to said last-mentioned conduit means; third conduit meansA operatively connected ton said settling tank and said first liquid inlet means and adapted to supply the same with quench media; fourth conduit means operatively connected to said fourth liquid withdrawal outlet means and adapted to pass condensate therefrom back to the downstream end of said reactor; fth conduit means operatively connected to said settling tank and adapted to pass water therefrom to direct heat exchange cooling means; and sixth conduit means operatively con-l nected to said last-mentioned direct heat exchange cooling means and adapted to pass the resulting cooled water therefrom back to said second liquid inlet means in said upper end of said contact tower.

16. Apparatus for quenching and scrubbing a gas recovered from the thermal conversion of hydrocarbons from a thermal reactor, which comprises, in combination; a two-stage gas-liquid contact tower intermediately divided by liquid collecting means, having a gas passage therein,

into lower and upper quenching zones; gas-inlet means in the lower part of said lower quenching zone; gas-outlet means inthe upper part of said upper quenching zone; iirst liquid inlet means in the upper end of said lower quenching zone; second liquid inlet means in the upper end of said upper quenching Zone; first liquid withdrawal outlet means in the lower end of said lower quenching zone; second liquid withdrawal outlet means in the lower end of said upper quenching zone -and adapted to withdraw liquid from said liquid collecting means; first conduit means operatively connected to iirst and second liquid withdrawal outlet means; a sub-atmospheric ash tower intermediately divided by liquid collecting means ti i3 into upper and lower zones; liquid inlet means in the lower part of said lower zone of said ilash tower and operatively connected to said first conduit means; an indirect heat exchanger disposed in said upper zone of said flash tower; third liquid withdrawal outlet means in the lower end of said lower zone of said flash tower; fourth liquid withdrawal outlet means in the lower end of said upper zone of said ashtower and operatively adapted to withdraw liquid from said last-mentioned liquid collecting means; second conduit means operatively connected to said third liquid withdrawal outlet means; a

Vliquid settling tank operatively connected to said lastrnentioned conduit means; third conduit means operatively connectedY to said settling tank and said iirst liquid inlet means and adapted to supply the same with quench 4media; fourth'conduit means operatively connected to said fourth liquid withdrawal outlet means and adapted to pass'condensate therefrom back to the downstream end of said reactor; fifth conduit means operatively connected to said settling tank and adapted to withdraw water therefrom; a second similar sub-atmospheric flash tower; third liquid inlet means in the lower portion of said sec- 'ondiiash tower and operatively connected to said fth conduit means; fourth liquid inlet means in the upper portion of said second flash tower; condensate collecting means in said upper portion of said second flash tower; sixth conduit lmeans operatively adapted to withdraw accumulated condensate from said last-mentioned collecting means and supply the same to said condenser in said upper zone of said first flash tower; and seventh conduit means operatively adapted to Withdraw condensate from the lower part of said second ilash tower and pass the same to said second liquid inlet means.

`References Cited in the file of this patent UNITED STATES PATENTS 2,322,056 Potts n lune 15, 1943 2,416,227 Seyfried Feb. 18, 1947 2,722,506 Ellis Nov. 1, 1955 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No 2,945'Yo75 July 12 1960 Raymond C Scofield It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column lO.i line 19, strike out "and", first occurrelflce.1

Signed and sealed this 4th day of April l9l (SEAL) A Attest: ERNEST W. SWIDER ARTHUR W. CRocKER 

1. A PROCESS FOR QUENCHING AND SCRUBBING A HIGH TEMPERATURE CRACKED GAS CONTAINED ACETYLENE RECOVERED FROM THE THERMAL CONVERSION OF HYDROCARBONS TO PRODUCE ACETYLENE, WHICH COMPRISES PASSING SAID HIGH TEMPERATURE CRACKED GAS INTO THE LOWER PORTION OF A TWO-STAGE QUENCHING ZONE, INITIALLY CONTACTING SAID CRACKED GAS IN THE LOWER PORTION OF SIAD QUENCHING ZONE WITH RELATIVELY COOLER QUENCH OIL IN COUNTERCURRENT FLOW, FINALLY CONTACTING SAID CRACKED GAS WITH QUENCH WATER IN THE UPPER PORTION OF SAID QUENCHING ZONE IN COUNTERCURRENT FLOW, WITHDRAWING THE RESULTING QUENCHING, RELATIVELY TAR-FREE CRACKED GAS CONTAINING ACETYLENE AS OVERHEAD FROM SAID UPPER PORTION OF SAID QUENCHING ZONE, WITHDRAWING LIQUID CONDENSTATE FROM SAID UPPER PORTION OF SAID QUENCHING ZONE, WITHDRAWING SPENT OIL FROM SAID LOWER PORTION OF SAID QUENCHING ZONE, PASSING SAID LIQUID CONDENSATE AND SPENT OIL TO THE LOWER PORTION OF A SUB-ATMOSPHERIC FLASHING ZONE TO EFFECT EVAPORATION OF A MINOR PORTION OF SAID LIQUID CONDENSATE AND CAUSE SAID SPENT OIL AND A MAJOR PORTION OF SAIOD LIQUID CONDENSATE TO SETTLE IN THE LOWER PORTION OF SAID FLASHING ZONE, CONDENSING THE RESULTING WATER VAPOR IN THE UPPER PORTION OF SAID FLASHING ZONE, WITHDRAWING WATER AND SAID SETTLED SPENT OIL FROM SAID LOWER PORTION OF SAID FLASHING ZONE AND CONVEYING THE SAME TO A LIQUID SEPARATION ZONE, WITHDRAWING OIL FROM THE LATTER ZONE AND PASSING THE SME TO THE UPPER END OF SAID LOWER PORTION OF SAID QUENCHING ZONE FOR USE AS SAID QUENCH OIL, COLLECTING LIQUID CONDENSATE ACCUMULATING IN THE LOWER END OF SAID UPPER PORTION OF SAID FLASHING ZONE, AND WITHDRAWING SAID LAST-MENTIONED CONDENSATE FROM SAID FLASHING ZONE FOR USE AS QUENCH AND SCRUBBING A GAS RE
 10. APPARATUS FOR QUENCHING AND SCRUBBING A GAS RECOVERED FROM THE THERMAL CONVERSION OF HYDROCARBONS FROM A THERMAL REACTOR, WHICH COMPRISES, IN COMBINATION A TWO-STAGE GAS-LIQUID CONTACT TOWER INTERMEDIATELY DIVIDED BY LIQUID COLLECTING MEANS, HAVING A GAS PASSAGE THEREIN, INTO LOWER AND UPPER QUENCHING ZONES, GAS-INLET MEANS IN THE LOWER PART OF SAID LOWER QUENCHING ZONE, GASOUTLET MEANS IN THE UPPER PART OF SAID UPPER QUENCHING ZONE, FIRST LIQUID INLET MEANS IN THE UPPER END OF SAID LOWER QUENCHING ZONE, SECOND LIQUID INLET MEANS IN THE UPPER END OF SAID UPPER QUENCHING XONE, FIRST LIQUID WITHDRAWAL OUTLET MEANS IN THE LOWER END OF SAID LOWER QUENCHING ZONE, SECOND LIQUID WITHDRAWAL OUTLET MEANS IN THE LOWER END OF SAID UPPER QUENCHING ZONE AND ADAPTED TO WITHDRAW LIQUID FROM SAID LIQUID COLLECTING MEANS, FRIST CONDUIT MEANS OPERATIVELY CONNECTED TO FIRST AND SECOND LIQUID WITHDRAWAL OUTLET MEANS, A SUB-ATMOSPHERIC FLASH TOWER INTERMEDIATELY DIVIDED BY LIQUID COLLECTING MEANS INTO AND UPPER AND LOWER ZONES, LIQUID INLET MEANS IN THE LOWER PART OF SAID LOWER ZONE OF SAID FLASH TOWER AND OPERATIVELY CONNECTED TO SAID FIRS CONDUIT MEANS, AN INDIRECT HEAT EXCHANGER DISPOSED IN SAID UPPER ZONE OF SAID FLASH TOWER, THIRD LIQUID WITHDRAWAL OUTLET MEANS IN THE LOWER END OF SAID LOWER ZONE OF SAID FLASH TOWER, FOURTH LIQUID WITHDRAWAL OUTLET MEANS IN THE LOWER END OF SAID UPPER ZONE OF SAID FLASH TOWER AND OPERATIVELY ADAPTED TO WITHDRAW LIQUID FROM SAID LAST-MENTIONED LIQUID COLLECTING MEANS, SECOND CONDUIT MEANS OPERATIVELY CONNECTED TO SAID THIRD LIQUID WITHDRAWAL OUTLET MEANS, A LIQUID SETTLING TANK OPERATIVELY CONNECTED TO SAID LASTMENTIONED CONDUIT MEANS, THIRD CONDUIT MEANS OPERATIVELY CONNECTED TO SAID SETTLING TANK AND SAID FRIST LIQUID INLET MEANS AND ADAPTED TO SUPPLY THE SAME WITH QUENCH MEDIA, AND MEANS OPERATIVELY CONNECTED TO SAID FOURTH LIQUID WITHDRAWAL OUTLET MEANS AND ADAPTED TO RETURN QUENCH MEDIA THEREFORM TO THE SYSTEM. 